RESUMO
BRCA1 and BRCA2 are the two most commonly mutated tumor suppressor genes associated with hereditary breast cancer (BC). Also, mutations in TP53, PIK3CA, PTEN and AKT1 were observed at a high frequency in BC with their mutation spectrum exhibiting a subgroup particularity with enormous clinical significance in the prevention, classification and treatment of cancers. Unfortunately, the mutation spectrum of these genes is still unknown in most Sub-Saharan African population. Therefore, using samples from 133 unselected BC patients, we aimed to assess the contribution of these mutations by direct Sanger sequencing. The analysis revealed pathogenic germline variants on BRCA1 exon 11 (c.3331C > T, 0.75%) and BRCA2 exon 11 (c.5635G > T, c.6211delA; 1.5%). Five other pathogenic variants were identified in 61 of the 133 subjects (45.86%), with 39.09% for PIK3CA, 12.78% for TP53. Interestingly, a variant in PIK3CA found in high frequency in our population was different from the one usually found in other populations (c.1634A > C, 38.34%), and four patients carried mutations linked to Cowen Syndrome 5 c.[1634A > C;1658_1659delGTinsC]. A novel variant (c.312G > T) was found in TP53 gene at 12.78%. Overall, mutation carriers were found more in Her2 negative and in patients that underwent surgery and chemotherapy. No pathogenic variant was found in PTEN and AKT1. Our population displayed a high frequency of PIK3CA mutations with an unusual distribution and spectrum as well as a relatively low prevalence of BRCA mutations. Our results provided novel data on an unstudied population and may help in prevention, and the establishment of suitable therapeutic approaches for our population.
Assuntos
Neoplasias da Mama , Proteína BRCA1 , Proteína BRCA2 , Burkina Faso , Classe I de Fosfatidilinositol 3-Quinases , Feminino , Predisposição Genética para Doença , Mutação em Linhagem Germinativa , Humanos , Mutação , PTEN Fosfo-Hidrolase , Prevalência , Proteínas Proto-Oncogênicas c-akt , Proteína Supressora de Tumor p53RESUMO
In this work, we proposed a sensitive and selective colorimetric assay for single nucleotide mutation (SNM) detection combining rolling circle amplification (RCA) and G-quadruplex/hemin DNAzyme complex formation. In the detection principle, the first step involves ssDNA hybridization with a padlock probe (PLP) DNA, which can discriminate a single base mismatch. The successful ligation is followed by an RCA event to generate an abundance of G-quadruplexes (GQ-RCA) which are then transformed into a DNAzyme (G-quadruplex/hemin complex) by the addition of hemin. The color change from colorless 3,3',5,5'-tetramethylbenzidine (TMB) into colored oxTMB when hydrogen peroxide (H2O2) is added indicated the presence of a mutation. The assay had a limit of detection (LOD) of 2.14 pM. Mutations in samples from breast cancer patients were successfully detected with an accuracy of 100% when compared to Sanger sequencing results. The method is easily applicable even in resource poor setting regions given that it doesn't require any sophisticated or expensive instruments, and the signal readout is detectable simply by the naked eye. Our assay might be a useful tool for genetic analysis and clinical molecular diagnosis for breast cancer risk assessment and early detection.
RESUMO
Genetic alterations in the TP63 (GenBank: NC_000003.12, ID: 8626) and CCR5 (receptor 5 chemokine co-receptor) (GenBank: NC_000003.12, ID: 1234) genes may increase the risk of developing breast cancer. The aim of this study was to investigate the probable involvement of polymorphisms rs17506395 in the TP63 (tumour protein 63) gene and the CCR5Δ32 mutation in the occurrence of breast cancer in Burkina Faso. This case-control study included 72 patients and 72 controls. Genotyping of SNP rs17506395 (TP63) was performed by polymerase chain reaction-restriction fragment length polymorphism, and genotyping of the CCR5Δ32 mutation was performed by allele-specific oligonucleotide polymerase chain reaction. For SNP rs17506395 (TP63), the genotypic frequencies of wild-type homozygotes (TT) and heterozygotes (TG) were, respectively, 27.72 and 72.22% in cases and 36.11 and 63.89% in controls. No mutated homozygotes (GG) were observed. For the CCR5Δ32 mutation, the genotypic frequencies of wild-type homozygotes (WT/WT) and heterozygotes (WT/Δ32) were 87.5 and 13.5%, respectively, in the cases and 89.29 and 10.71%, respectively, in the controls. No mutated homozygotes (Δ32/Δ32) were observed. None of the polymorphisms rs17506395 of the TP63 gene (OR = 1.47, 95% CI = 0.69-3.17, P = 0.284) and the CCR5Δ32 mutation (OR = 1.32, 95% CI = 0.46-3.77; P = 0.79) were associated with the occurrence of breast cancer in this study.
RESUMO
BACKGROUND: Genetic alterations can result in DNA repair defects, increasing susceptibility to breast cancer. The aim of this study was to evaluate the involvement of two DNA repair genes, ERCC1 (rs3212986, GenBank NC_000073.9) and ERCC2 (rs1799793, rs13181, GenBank: NC_000019.10) in the occurrence of breast cancer in Burkina Faso. METHODS: This case-control study enrolled 128 participants including 64 patients and 64 healthy controls. Genotyping of polymorphisms were performed by real-time PCR and PCR-RFLP. RESULTS: The heterozygous AC genotype of the ERCC2rs13181 polymorphism was associated with the occurrence of breast cancer when the mutant allele is inherited under the dominant pattern (CC/AC vs AA; OR = 2.74, 95% IC (1.09-6.87); p = .028), but this association became insignificant after the Bonferroni correction (p = .156). No association was observed between ERCC1rs3212986 and ERCC2rs1799793 polymorphisms and breast cancer risk. CONCLUSION: This study showed that the heterozygous genotype (CA) of the ERCC2rs13181 polymorphism may be associated with a risk of breast cancer.
Assuntos
Neoplasias da Mama , Proteínas de Ligação a DNA , Endonucleases , Proteína Grupo D do Xeroderma Pigmentoso , Feminino , Humanos , Neoplasias da Mama/genética , Burkina Faso , Estudos de Casos e Controles , Reparo do DNA , Proteínas de Ligação a DNA/genética , Endonucleases/genética , Polimorfismo de Nucleotídeo Único , Proteína Grupo D do Xeroderma Pigmentoso/genéticaRESUMO
Introduction: Human herpesvirus type 8 (HHV-8) is the main etiological agent of Kaposi's sarcoma. This virus is frequently associated with immunocompromision. This study aimed to detect HHV-8 in people with compromised immune system. Patients and Methods: This is a cross-sectional study that included 180 subjects: 179 HIV-infected patients and 1 patient with bullous pemphigoid. Blood samples were taken from all subjects, and swabs of lesions were then taken from individuals with symptoms of Kaposi's sarcoma. Viral load and CD4+ T lymphocytes count were performed for persons living with HIV and real-time PCR detection of HHV-8 DNA was performed in all subjects in the study. Results: Among HIV-infected persons, 13.41% had a viral load of more than 10,000 copies/mL, and 22.91% had a CD4+ T lymphocytes count of fewer than 350 cells/µL. A total of four (three HIV-1 infected patients and one patient with bullous pemphigoid) patients (2.22%) had apparent lesions of Kaposi's sarcoma. In the plasmas and swabs from associated lesions, HHV-8 DNA was found in only two individuals, with an HHV-8 prevalence of 1.11% (2/180) with 0.55% (1/179) in an HIV-infected patient on antiretroviral therapy. Conclusion: These results exposing low prevalence levels of HHV-8 in HIV-infected patients could be due to the beneficial effect of antiretroviral drugs.